Quick silly dilution question

1. The problem statement, all variables and given/known data
The mols of ethanol is 1.72x10^-4. I am trying to find its volume. However, I am confused on what the molarity of this solution is. (Molarity here is in mol/L)

(the 10mL sample contained 1.72x10^-4 mols of ethanol, but it was diluted in 90 mL water)

The lab said:
"Dilute the 10.0 mL ethanol sample as such: (10.0 mL ethanol in 90.0 mL of distilled water, for a total of 100.0 mL)."

3. The attempt at a solution

The mols of ethanol is 1.72x10^-4. Do I divide this figure by .01 liters? Or do I do it by .1? I think it's one or the other but either way I need this calculation perfect or the rest of the lab is moot!

The original dilution scheme was 10 mL of the ethanol in 90mL water [I think my teacher isn't really concerned with the negligible detail(s)]

1.72x10^-4 mols of ethanol is the mols of ethanol oxidized by dichromate ion in my lab. I am trying to find the volume of those mols. The procedure included preparing a solution by adding 10 mL ethanol into 90 mL of water. We shook it up and added into a seperate flask 1 mL of that solution and 21 mL of 0.01M dichromate in 5M H2SO4.